


Undercover(s)

by plutonianshores



Category: Dublin Murders (TV)
Genre: Edging, F/M, Femdom, Undercover as Married
Language: English
Status: Completed
Published: 2020-05-08
Updated: 2020-05-08
Packaged: 2021-03-02 17:47:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,358
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24080821
Author URL: https://archiveofourown.org/users/plutonianshores/pseuds/plutonianshores
Summary: Frank Mackey's undercover identity needs a wife, and Cassie reluctantly agrees to play her. The line between playacting and their own feelings isn't so much blurred as entirely rubbed out during the course of the investigation
Relationships: Frank Mackey/Cassie Maddox
Comments: 8
Kudos: 5
Collections: Id Pro Quo 2020





	Undercover(s)

**Author's Note:**

  * For [Ashling](https://archiveofourown.org/users/Ashling/gifts).



Working with Frank Mackey, Cassie had gotten used to hearing a lot of shite. She was pretty sure nothing could surprise her anymore, but Frank always did have a way of proving her wrong.

"Cassie!" he said, grinning like a loon. "I’ve been waiting for you. I need a wife."

It took her a moment to even process what he’d said. Luckily, Cassie was good at keeping her reactions to herself, something that had served her well both while she was undercover and working with Frank. "I thought you’d tried that already. But if you’re so keen to get back on the market, I hear Nolan’s sister is single."

Frank shuddered. "Nolan would skin me alive for going near her. And it’s not Frank Mackey who needs a wife, it’s Gerry Byrne."

An undercover thing, then. Frank-as-Gerry was in deep with some sort of smuggling ring (he was cagey with the details, like he always was about his cases). "Aren’t I a little young for him?"

"Nah," Frank said, "you’re a trophy wife. The head honcho’s got a wife I’m sure I could get talking, but he doesn’t let her talk alone with any men. So I’m bringing in my wife Sinead, who’s been vacationing in Ibiza this past month."

"Better work on my tan."

"Don’t worry, love, I’ll get you all dolled up." Frank grinned.

  
  


Frank took control of the makeover, like he always did. Cassie made all of the decisions, like always, but the physical touches? All him. He was too much of a control freak to risk the bleach frying her hair or the nose piercing coming out crooked. (Cassie drew the line at a nose piercing. It would look all wrong if she walked in there tomorrow with a healing hole in her face when it should have been years old – no one got their nose pierced in Ibiza.)

As they got her looking like Sinead, she and Frank set out to build her, and to get Cassie familiar with Gerry. The thrill of building an entire new person still sent a shot of adrenaline right into Cassie’s chest. It was what kept her in Undercover even with the horrific hours and the nonexistent work-life balance. Once a new identity got its hooks in her, she took off like going over that first big hill on a coaster, racing along until the alter ego took on a life of her own.

Sinead and Gerry had met at a yacht party a few summers ago. Gerry said he loved her optimism, but really he liked her tits; Sinead said she liked his rugged good looks, but really she liked his pocketbook. Gerry sent Sinead off on holiday whenever he had to focus on work, which meant Sinead was off on holiday a good portion of the year. The sex when she came back was enough to keep Gerry devoted to bankrolling her and, since Frank had been using her as an excuse to avoid the girls provided by the big boss, committed to keeping his trousers zipped.

The man in their crosshairs, Johnny Tucker, didn’t harbor disobedience, and he didn’t want anyone talking about his operation to people he hadn’t personally vetted. So Sinead knew nothing about him, although Cassie had wheedled a bit of information out of Frank (‘this is not the time to go all method, you prick!’). He liked his whiskey and he liked his women, although recently he’d fallen fast and hard for the beautiful and empty-headed Ciara. He kept her far away from any men she might fuck, but more surprisingly, he’d kept his hands off of the veritable harem of sex workers and hangers-on that he’d gathered while building his smuggling empire.

"Ah, true love," Frank said, wiping an imaginary tear from his eye. "But Ciara, it seems, is lonely. And that’s where you come in, my darling Sinead."

Frank had his plastic-gloved hands in her hair, rinsing the bleach out in the bathroom sink. Each drag of his fingers sent a little shiver down her spine, a shiver she was telling herself was down to Gerry and Sinead’s chemistry. You heard about bleedthrough, people coming out of time undercover with some of the mannerisms or cravings they’d adopted for the job. Cassie and Frank were already close, and if that was tipping over into some easily-ignorable feelings after they’d spent near on an hour discussing in detail what their married life was like, well, that just meant she was doing her job.

"You think she’ll like me? You didn’t exactly design Sinead to be likable."

Frank scoffed, offended. "Who wouldn’t like my beautiful wife? Nah, listen, she’s been locked up in Tucker’s flat for so long with only a bodyguard for company that she’ll jump at any opportunity for feminine companionship."

"And Tucker won’t peg me as a threat?" He wasn’t jealous enough to keep Ciara shut away just to keep her from cheating, or Cassie would have been half tempted to pass a lead over to Domestic. He’d caught wind that someone was sniffing around him, although he didn’t know it was the Gardaí.

"I’ve established myself as firmly above suspicion, and I’m not sure the fellow is capable of viewing women as a threat."

Cassie let Frank guide her up and pat her hair dry. "Lovely."

"You’re not the one who’s been eating supper with him six nights out of seven." Frank shuddered. "I’ve heard more about his lays than I ever wanted to. Trust me, you’re getting off easy with Ciara."

The air was cold against Cassie’s scalp, and she felt the loss of Frank’s touch acutely. "Right, then," she said, shaking the feeling away, "when do we start?"

  
  


Cassie’s first night as Sinead boiled down to one hour at Tucker’s club with Ciara (just as ditzy as promised, and growing fond of Sinead) and a whole night ahead of them in the hotel room Tucker had rented for them.

"I missed you, love," Frank said, sitting down on the bed hard enough to make the springs creak. He grabbed for the pad of paper on the nightstand, ripping the sheet off the top and setting it on his thigh to write (no imprints left behind). _He’s prob not_ _listening_ _._

Cassie raised an eyebrow and held her hand out for the paper. _He might be_ _listening_ _, paranoid SOB_. They’d been working together long enough that their minds ran along the same track, crashing in the middle of the same train of thought. Sinead had just gotten back from a monthslong holiday abroad. When Gerry and Sinead reunited, they had earth-shaking, headboard-breaking sex. There was a nonzero chance that Johnny Tucker, paranoid bastard that he was, might have chosen his room to allow him to listen in and make absolutely sure Gerry hadn’t been lying to him about the earth-shaking, headboard-breaking sex that kept him faithful to his wife.

There was an unspoken understanding in Undercover that sex was part of the gig. Sure, you tried to get out of it if you could, but sometimes your cover depended on fucking. Cassie didn’t mind that. At the end of the job, she could walk away and never have to see anyone her old identity had known again, and there was something thrilling about staying in character through the whole thing. Sleeping with Frank, someone she had to face in the office when this wrapped up...that was another beast entirely. The worst bit was that she _definitely_ wanted to fuck him. (Just Sinead talking, she told herself.) At the end of all this, Cassie was going to go back to her desk and Frank was going to go back to his office and when they saw each other at the coffeemaker or at the whiteboard they were going to _know_ the noises Frank made when he came and the exact location of all of Cassie’s moles. No going back from this.

Cassie tackled Frank into a kiss. Their lips met awkwardly at first, trying to figure out how they fit together, and thank _God_ this hadn’t happened in public, and then something clicked. Frank’s lips parted under Cassie’s, surprisingly soft, and he moaned when she nipped at him.

" _Fuck_ , darling," he said when she pulled apart to breathe. "I missed you."

"Were you good while I was gone?" Tucker already thought she was leading Gerry around by the sack, might as well lean into it.

"So good," Frank gasped. "I thought of you every time I touched myself."

Oh, he caught on fast. Cassie cupped his dick through his trousers, rubbing it harshly through the fabric. "You remembered that this belongs to me?"

"Always." Frank caught her mouth in another kiss, muffling his little groans in her lips. Cassie kept her eyes open, watching his reactions, figuring out just how to touch him to get him desperate. Then she pulled back, leaving him shaking with desperation.

"Since you’ve been so good, I’m going to make this last." Cassie smoothed his hair down.

Frank gave her a crooked grin, and said, with no trace in his voice of the sarcasm writ clear across his face, "God, I love you."

"I know what you need." Cassie planted her hands on Frank’s chest and nudged him down onto the bed, fingers fumbling with his fly. She got his dick out, and Frank shimmied out of his trousers. Cassie hitched her skirt up and flung off her thong, giggling (more Sinead) as they caught on the lamp.

Frank tsked. "So impatient."

"You’ve been too busy. I missed you too, you know." Cassie brushed her arse against Frank’s dick, holding his hips down as he tried to buck up. "Tell that boss of yours to give you more time off."

"Let’s not talk about my boss right now." Frank leaned back, his eyes fluttering shut.

Cassie smirked and leaned back on her heels, slowly stroking him from root to tip. He held still, which sent a thrill right to Cassie’s cunt. Frank always had been a quick study. She was going to learn every inch of him, every place where a gentle stroke or a hard pinch would make him fall apart. If Frank intended to let her have her way with him, she was going to take full advantage. Frank Mackey, entirely at her mercy, and he was letting it happen.

She bent down to drag her teeth over his chest, catching on his nipple. That made him buck up into her again, abs tensing underneath her. "Don’t move, love," she said.

"I’m trying." Frank sounded distraught at the reprimand, but his exaggerated eye roll said otherwise. Well, he’d let her run the show, he’d have to put up with what Sinead would want.

Cassie kissed her way across his torso, withdrawing from his cock entirely. She intended to learn every inch of Frank tonight, no matter what he thought of the matter. She felt every hitch in his muscles under her lips, felt him putting everything he had into staying still for her. Cassie wondered if she could get Frank to do this when he wasn’t in character as Gerry – but no, there wouldn’t be another time, she told herself. She didn’t _want_ there to be another time, not really, even if the thought made her heart race.

Frank was wiry, deceptively strong for his slim frame. He had a ticklish spot on his side, where the brush of a kiss made him jump up even as he tried to keep still, glaring silently at her. She’d have to remember that (not for next time, there wouldn’t be a next time).

Cassie skipped right over his cock to trace down his thighs, stopping when her lips brushed something rough. A nasty gouge that must have cut near to the bone, leaving a divot in Frank’s leg even after it had healed. She wanted to ask, but Gerry would have told his wife about the scar already, or more likely Gerry wouldn’t have one at all. So Cassie raised an eyebrow at him and traced her tongue up the crease of his hip, making him bite back what she knew must have been a curse, although he disguised it well.

It must have been painful, how hard Frank was. He whimpered every time she touched him now, face flushed red and eyes shut tight. She wanted this – _Cassie_ , not Sinead. It had never really been Sinead, underneath, even if the flourishes were her. Cassie gave Frank one last stroke and then guided him into her, taking him in one smooth motion. She was so wet for this, so ready for something filling her, and although Frank didn’t say anything she could see the recognition on his face. He’d forgotten about speaking entirely now, watching her with awe on his face.

"I love this," she whispered into his ear, riding him hard and sloppy. "Watching you come apart."

Frank caught his lip between his teeth, grabbing her hips in a vise-tight grip. He didn’t trust himself to speak, Cassie realized, didn’t know that the words that came out would sound more Gerry Byrne than Frank Mackey.

Neither of them lasted. Cassie got one hand on her clit and came at the first touch, Frank following her over when she tightened around him. She rode him through the aftershocks, ignoring his quiet whimpers.

They lay face to face afterwards, Cassie’s pulse slowly coming back down. She committed the lines of Frank’s face to memory, tracing the parentheses framing his mouth and the wrinkles of his forehead.

"Have you heard anything, in the entire time we’ve been here?" Frank asked.

Cassie shut her eyes, thinking about the lush silence that had enveloped them as soon as they’d shut the door. Even the traffic outside wasn’t audible. Expensive room, thick walls. "He couldn’t hear us," she said, following where Frank was leading. They’d both known that, deep down, a quiet part of Cassie said. She shoved that part even further into the recesses of her mind, and opened her eyes back up to see Frank’s sheepish smile.

"Think of it as a character-building exercise."


End file.
